To calculate the overall star rating and percentage breakdown by star, we don’t use a simple average. Instead, our system considers things like how recent a review is and if the reviewer bought the item on Amazon. It also analyses reviews to verify trustworthiness.
Paying for reviews???? You too??? This invalidates those reviews. You obviously have enough knowledge and resources to put out a nice book, why not let the audience speak for themselves without bribing them, it would mean a lot more to those of us who depend on honest reviews.